THE CHEMISTRY OE THE ANIMAL BODY. 515 



phates, while to primary sodium phosphate carnivorous urine mainly owes its 

 acid reaction. 



In speaking of the ash of protoplasm, Nencki 1 advocates the idea of separate 

 combinations of the base and acid radicles with the proteid molecule, as, for 

 example, the sepauate union of potassium with proteid and of phosphoric acid 

 with proteid, in the functionally active cell. However combined, phosphoric 

 acid is necessary for the organism. 



Phosphorus in the Body. — The principal source of supply is derived 

 from the phosphates of the alkalies and alkaline earths in the foods ; it may be 

 absorbed in organic combinations in nuclein, casein, and caseoses ; and it may 

 perhaps be absorbed as glycerin phosphoric acid, which is an intestinal decompo- 

 sition product of lecithin 2 and probably also of protagon. Phosphorus leaves 

 the body almost entirely in the form of inorganic phosphate, the only exception 

 being glycerin phosphoric acid, which has been detected in traces in the urine. 

 In man and carnivora the soluble primary and secondary phosphates of the 

 alkalies are found in the urine, together with much smaller amounts of the 

 less soluble primary and secondary phosphates of the alkaline earths. There 

 is likewise, even during hunger, a continuous excretion of tertiary phosphate 

 of calcium, magnesium, and iron in the intestinal tract. In herbivora the ex- 

 cretion is normally into the intestinal tract, and no phosphates occur in the 

 urine. This is because herbivora eat large quantities of calcium salts which 

 bind the phosphate in the blood, and they likewise eat organic salts of the 

 alkalies, which become converted into carbonate and appear in the urine as 

 acid carbonates ; such a urine has no solvent action on calcium phosphate. 3 

 In a similar manner a great reduction of phosphate in the urine of man may 

 be effected by feeding alkaline citrate and calcium carbonate, the first to furnish 

 the more alkaline reaction to blood and urine, the second to bind the phosphate 

 in the blood. The more alkaline reaction itself is insufficient to prevent the 

 appearance of phosphates in the urine. 4 On the other hand, starving herbiv- 

 ora, or herbivora fed with animal food, give urines acid from primary phos- 

 phate. 5 In diabetes where there is a large production of abnormal acids 

 which tend to neutralize the blood, there is a more acid urine which contains 

 an increased amount of calcium phosphate, and the excretion of the same 

 through the intestinal wall correspondingly decreases. During lactation the 

 amount of phosphate eliminated through the ordinary channels is decreased, 

 for a considerable amount is used to form the milk. 7 



Excreted phosphates may be originally derived from the phosphates of the 

 bones, or from phosphates arising from the oxidation of nuclein, protagon, and 

 lecithin, but by far the greater quantity is derived from the food, or from pro- 



1 Archiv far exper. Pathologie und Pharmakologie, 1894, lid. 31, S. 334. 

 - B6kay: Zeitichrift fur phynologisehe Chemie, l s 77 78, Bd. 1, S. 157. 



3 J. Bertram : Zeitsehrift fur Biologie, 1878, Bd. 14, S. 354. * Op. cit., S. 354. 



4 Weiske: Ibid., 1872, Bd. 8, S. 246. 



6 Gerhardt und Schlesinger : Archiv far exper. Pdlhohf/ie und Pharmakologie, L899, Bd. 12, 

 S. 83. 



7 Paton, Donlop, and Aitchison : Journal of Physiology, 70 . xxv. p. 212. 



